Many produce products are harvested and packed in the field into containers, which are ultimately purchased by the end consumer. Examples of such produce items include, but are not limited to, strawberries, raspberries, other berries, tomatoes, grapes, mushrooms, radishes and broccoli florets. Many of these produce items require substantial post-harvest cooling in order to enable shipping over long distances and to prolong shelf life.
In use, a grower's harvesting crew harvests produce items of the type previously discussed directly from the plant in the field into the container. The containers are then loaded into trays, which contain a specific number of individual containers and the trays, when filled, are loaded onto pallets. After the pallets have been filled and loaded, they are transported to shippers who perform a variety of post-harvest processes to enhance the marketability of the produce itself. For many types of produce, including berries, the packed fruit is then cooled. Commonly berries are cooled by injecting cooling air into one side of a tray and passing the cool air through the individual baskets inside the tray and around the berries stored therein. As the air cools the berries, it picks up heat therefrom which is exhausted from apertures on the opposite side of the tray.
Existing systems are effective at cooling the fruit containers at the outside edges of the trays, but less effective at cooling the fruit in the centers of the trays. This problem is exacerbated when many trays are loaded together on a pallet (and worse still when many pallets are stacked together in a refrigerated transport compartment). The pallet and tray stacking can inhibit the cooling airflow to the extent that the innermost fruit remains relatively warm compared to the cooler outer fruit. This can lead to spoilage in some of the fruit. In order to reduce spoilage, conventional approaches use excessive cooling temperatures to cool the produce. This is relatively effective at cooling the innermost fruit, but is an expensive solution due to higher cooling costs. Additionally, an undesirable consequence of such excess cooling is that the outermost fruit can freeze or nearly freeze resulting in unacceptable product damage. Thus there is a need for a packaging system that can achieve more efficient cooling airflow through the trays and baskets thereby facilitating more even and efficient cooling of produce.
It is noted that some of these cooling problems are addressed by the prior art, notably U.S. Pat. Nos. 5,738,890, 6,074,676, and 6,074,854, held by Sambrailo Packaging. While the inventions taught and claimed in U.S. Pat. Nos. 5,738,890, 6,074,676, and 6,074,854, incorporated herein by reference, provide hitherto unmatched cooling for produce items, improvements can be made.
Among the needed characteristics are reduced cooling times and improved coolant circulation leading to reduced cooling expense for the fruit contained in the baskets. Moreover, it is desirable that improved airflow be supplied through the trays and baskets of the system in order to maximize air transfer rates. Additionally, an enhanced ability to pass cooling flows underneath produce containers in multiple directions is desired. Also, such a system can be configured to integrate with commonly used and preferred shipping formats, for example, in the United States such a system would be compatible with forty by forty eight inch pallets in current use in the grocery industry. Moreover, where different pallet sizes are the standard, for instance in another country, what is further needed is a system which can be scaled to effect the advantages hereof in that pallet system.